At most audio performances today, some sort of amplification system is used in order for the sound to reach its audience, via TV, radio or via a speaker system. Such an amplification system normally delivers a single output signal (or two, if the signal is a stereo signal). However, that single output signal has to be composed of all the audio sources that are to be relayed to the audience. In a limited setting, with only one or a few speakers or singers, a single microphone is enough to receive all sources. At larger settings, such as live concerts of e.g. operas, theatres, musicals, rock or pop concerts, classical music concerts or similar events, a large number of sources, often spread out over a large area, needs to be relayed to the audience. In such a case, a large number of microphones needs to be used, often one microphone per source. The signal from each microphone is assigned its own channel, via a cable or a wireless transmission system, and may be received and recorded individually. However, at some point all channels need to be merged into a single channel (or into two channels in a stereo application), which may be relayed to the audience by e.g. amplification, broadcasting or recording.
A device commonly used for merging the channels is a mixing console 1, which is shown in FIG. 1. Mixing consoles are well known to any one involved with the recording or performance of music. Basically, the mixing console consists of a number of input channels that are added in order to form a single output channel.
Typically, one input channel 11a, 11b and 11c is assigned to each audio source, such as a microphone 10a, 10b and 10c, a CD player or any other audio source. Each channel may have its own equalizer 12a, 12b and 12c for adjusting its audio properties, and a level control 13a, 13b and 13c for controlling its contribution to the output channel 14. The mixing console may further comprise auxiliary blocks for enabling the outputting or listening-in to individual channels. It may also comprise a compressor gate for providing a compressed signal, which is suitable for radio broadcast. Mixing consoles may also be implemented with software user interfaces.
The output channel 14 may be connected to any downstream equipment, such as an amplifier 2 supplying signals to a speaker 3, broadcast equipment 4 for broadcasting signals to receivers 5 or equipment 6 for producing media such as CDs, tapes etc. The output channel typically has its own level control for controlling the output level from the mixing console.
It is easily realized that if each channel has its own equalizer, its own level control as well as its own input connector, the mixing console may become very large, especially since a mixing console may have a very large number of input channels. For example 32 or 48 channels is common, but there are also much larger mixing consoles for managing a large number of audio sources, such as an orchestra. However, in addition to becoming bulky, such mixing consoles have a tendency to become both heavy, expensive and difficult to operate. Needless to say, this could become a problem for any traveling performance group and for other applications where a large number of microphones needs to be repeatedly set up and disassembled, such as rehearsal studios, theatres, TV-studios etc.
It is generally not a very good idea to increase the number of sources that may be connected to a mixing console by connecting them via a splitter, so that two or more microphones become connected in parallel to one input channel. However, the number of microphones that may be connected in this manner is generally limited by the power supplied from the mixing console and by the microphones' characteristics. Typically, not more than two microphones may be connected to an input channel in this manner, and it is not recommended since the interdependence between the microphones may affect the sound quality negatively. Furthermore, this does not enable any control of the microphones' panning or signal levels.
Hence, there is a need for a device which enables a larger number of sources to be connected to a mixing console or an amplifier.